Apparatus for heat sealing thermoplastic strips about elastic elements



APPARATUS FOR HEAT SEALING THERMOPLASTIC STRIPS ABOUT ELASTIC ELEMENTSFiled NOV. 16, 1946 2 Sheets-Sheet -l 92 i 533 4U 45 f o 7 Q1 '26 25 as3 44 27 44a 5 7 26 2 41 0 44b 34) a 32 8g 37 50 4o 4L I 44b 21 oai Q3 Q2I 1 l 6 i2 i INVENTOR 9 SidneyH. a id 3 9X 9a BY xlfluuq ATTORNEY April5, 1949. s. H. MAGID 2,466,643

APPARATUS FOR HEAT SEALING THERMOPLASTIC STRIPS ABOUT ELASTIC ELEMENTSFiled Nov. 16. 1946- 2 Sheets-Sheet 2 1/ III]! \I %fiAZ/lllllll iO6 77-j75 1 75 4s 07 79 78 76 Q? INVENTOR Sidne id Patented Apr. 5, 1949 UNITEDSTATES PATENT OFFICE APPARATUS FOR HEAT SEALING THERMO- PLASTIC- STRIPSABOUT ELASTIC ELE- MENTS This invention relates to an apparatus for ap-'plying or affixing elastic elements to articles fabricated of plasticsheet material, such as Polythene, Pliofilm, Vinylite, etc., having anelastic element at one end thereof (e. g., bowl covers) r at both ends(e. g., lamp shade covers) or at three or more points thereof (e. g.,baby pants which have three elastic elements, two at the leg openingsand one at the waist).

The principal object of the invention is an apparatus for applying andsealing the elastic element or elements in the plastic sheet article atthe proper place or places and to do so automatically, rapidly andcheaply.

For the attainment of this and such other objects as may appear or bepointed out, I have shown several embodiments of my invention in theaccompanying drawings, wherein:

Fig. 1 is an elevational section of the apparatus for applying theelastic element to an open end of a tubular article, such as a bowlcover;

Fig. 2 is a transverse section taken on the line 22 of Fig. 1;

Figs. 3, 4 and are enlarged fragmentary views explaining the operation;'Fig. 3 showing a portion of the plastic sheet article in positiontogether with the elastic element before the latter is released; Fig. 4shows the parts after the elastic element has been released; and Fig. 5shows the parts after the machine has operated to effect the sealing ofthe elastic element;

Fig. 6 is an elevational section of the apparatus for simultaneouslyapplying two elastic elements to the plastic sheet article, e. g. atboth ends of alamp shade covering; v

Fig. '7 is an elevational section 'of the singleelastic apparatusmodified for a different type of electrical. heating;

' Fi 8 is an elevational section of the appara- Referring first to Fig.l, the apparatus comprises two main parts, viz., a circular plate orhead It and a cylindrical, hollow body member 20 which rests on, and issecured to, a base 9.

For facility in illustration, headplate l9 and body member Zll are shownas circular and cylindrical, but it will beapparent that these may haveany desired sectional or transverse outline.

Head plate III is mounted for a limited extent of elevational movementrelative to body member 20. For this purpose there is provided withinthe body member and preferably centrally located, a mounting plate 1which is supported from the floor of body member 20 .by posts 6 ofsuitablev electrical-insulating material. Mounting plate I has a centralopening 5' which serves as a bearing for a vertical spindle 30, theupper end of which is received in a central opening l9 of head plate 10.Spindle 30 has a collar 31 which underlies mounting plate '1 and acollar 39 which underlies head plate It. Interposed between the collar39 and themounting plate I is a compression coil spring 4. The parts areso designed, and collars 31, 39 so positionally secured to the spindle(as by the set screws shown) that normally spring 4 maintains head plateIll in its elevated position, as shown, in which position there is apredetermined, relatively short distance between the underside of thehead plate and the annular, upper edge of the body member.

The upper edge of the body member has an'inwardly-disposed annularrecess 2! which results in an outwardly-disposed annular lip 22, seealso detail Fig. 3. Secured to the interior surface of body member 20and disposed at its upper end to project upwardly therefrom is a narrowtube or ring 23 of suitable electrical-insulating material. Theunderside of head plate It has an annular groove l3 which is disposedand dimensioned to receive the said upwardly projecting portion ofinsulating tube or ring 23. The outwardly-disposed, annular surface ofthe head plate is designated l2.

The parts are shown in detail in Fi 3 in the normal upward position ofhead plate Ill. The first step is to place the plastic sheet article,which is assumed to be tubular (designated P), in position about theapparatus so that a predetermined portion thereof, P, extends above thespace between head plate l0 and body member 20. Elastic element E isplaced about the tubular article P at the said space, Fig. 3, intensioned condition and then released, whereat it enters the spacebetween head plate Ill and body member 20, Fig. 4, crimping or foldingthe plastic sheet inwardly to present opposing portions-P and P inwardcontraction of the elastic element is blocked by abutment with theinsulating tube or ring 23, as clearly shown in Fig. 4. Head plate. I0is next moved downwardly, as shown in Fig. 5, (the upper portion ofinsulating tube 23 entering annular groove I3 of the head) to clampportions 19*, P between its annular portion I2 3 and annular lip 22 ofthe body member 20, the elastic element E and the bight of the loopedportions P P being received in annular recess 2| of the body member.

While compressed together, Fig. 5, portions P and P are fused or adheredtogether by local application of heat. I have found electrical heatingto be well suited; the particular type of heating known as di-electricheating'is shown in Figs. 1, 3-5, and also Fig. 6 (a second type ofelectrical heating will be described subsequently with reference to Fig.7). Referring to Fig. 1, base 9, which is metal and conductive, rests oninsulating feet 3 and is provided with a binding post 2 for electricalwire 28. Body member 20 has an opening 29 for a second electrical wireI8 which connects to a binding post i on mounting plate I. Wires I8, 28are connected to a high-frequency generator (not shown) to supplyhigh-frequency potential to head plate Ill and body member 20, i. e.,across the space separating the two, see Fig. 1 and Fig. 5. The currentpath at wire 28 is: 28, base 9, and body member 20. It will be observedthat insulating posts 6 and feet 3 confine the electric flow to thispath. The current path at wire I8 is: I8, mounting plate 1, spindle 30,and head plate Hi. It will thus be seen that the insulation posts 6prevent short-circuiting between the said two circuits. The circuit tothe high-frequency generator is completed by a switch (not shown) whenthe head plate I is brought down to bear on the article portions P Pinterposed between it and the body member 20, whereas heat of highintensity is generated by di-electric action across the annular lip 22of the body member and annular surface. 12 of the head plate, causingfusion of plastic material P P and an effective sealing in position ofelastic element E.

The apparatus, Fig. 6, for simultaneous sealing of two elastic elementshas a head plate in which i is similar to the one described above withreference to the single-elastic apparatus of Figs. 1 to the body memberdiffers in that it is tubular and has no floor as in Fig. 1. The upperend of tubular body member 20' is similar to that described in Figs. 1to 5 and accordingly these parts thereof bear the same referencecharacters. The lower end of the body member has similar annular lip 22'and annular recess 2|. Underlying its lower end is a bottom plate [0which is similar to head plate ill in that it has a similar annulargroove I3 and annular surface 12'. An insulating ring or tube 23' issecured to the lower end of body member 20. Bottom plate l0 rests on abase 9 similar to that of Fig. 1 except that it is provided with acentral opening and bearing So for vertical spindle bottom plate l0itself has a central bearing opening Ilia for the spindle. Spindle 30'has a collar 3| underlying base 9 and a collar 32 spaced above thebottom plate I0. interposed between collar 32 and bottom plate I0 is ahelical compressive spring 4L. The spindle has a third collar 34 inunderlying relation to a carrier member 24 slidable on the spindle;carrier member 24 underlies a plate 26 of insulating material, having aflange 21 at its outer edge which is secured to body member 20'. Plate26 has a central opening 26' in which is reserved a hub portion 25 ofcarrier member 24. Plate 26 is secured to carrier member 24. A fourthcollar 33 is secured to the spindle; interposed between collar 33 andthe hub portion 25 is a compression helical spring 4U.

The tubular plastic fabric (not shown) is placed about the apparatuswith one end, at which one 4 of the elastic elements is to be sealed, atthe upper end (lip 22 of the body member and head plate ID) of the bodymember and with its other end, at which the other elastic element is tobe sealed at the lower and (lip 22 of the body member and bottom platell). The elastic elements (not shown) are placed at the upper space(head plate Ill) and at the lower space (bottom plate III), the partsbeing positioned similarly to their positioning on the single-elasticapparatus of Figs. 1 to 5. A force is applied to the head plate ill; theresulting operation of the apparatus will depend upon the relativestrength of the two compression springs 4U and.4L. Assuming that thelower spring 4L is weaker than upper spring 4U, the forceapplied to headplate ill will lower it and spindle 30', all its collars including uppercollar 33 and, through the stronger compression spring 4U, the carriermember 24, plate 26 secured thereto, and body member 20'. Consequently,the lower annular lip 22 of the body member approaches the annularsurface l2 of the bottom plate I0, lower spring 4L being contracted, andpresses together the two folds of the material (not shown in Fig. 6, butsee detail Fig. 5) Further downward pressure on head plate I0 will nowovercome the resistance of upper spring 4U and cause head plate In toapproach the upper annular edge of body member 20', pressing togetherthe folds of the material at the upper end of the apparatus.

After the lower edge of the body member has been forced towards thebottom plate I0 and the head plate ID has been forced towards the upperedge of the body member, the control switch is closed to cause the foldsof the plastic material at the upper end of the apparatus and at thelower end, to be fused together by electrical, dielectric heat, in themanner described with reference to the single-elastic apparatus of Figs.1-5. One wire 28' from the high-frequency generator is connected to base3 and conducts current to the bottom plate l0, which rests directly-onthe base, and to the head plate l0 view the spindle 302. This potentialis not conducted to the body member 20' because of the presence ofinsulating plate 26. The other wire l8 from the high-frequency generatoris connected directly to body member 20'; wire l8 passes through anopening 9 in base 9 and an aligned opening HI in bottom plate l0.

Instead of di-electric heating, as in Figs. 1-5 (single elastic) and inFig. 6 (double elastic), conductive heating may be employed, as in Fig.'7 which shows a single elastic apparatus similar to Fig. 1. In thiscase, head plate Illa has an annular band H of electrical conductingmetal which serves as an electrical heating coil, the electricalcurrentbeing conducted thereto at two diametrically opposed points. Oneof the electrical wires is designated Ma, and the other, b. Twodiametrically opposite recesses II, II are provided in head plate lid toaccommodate the connecting ends of wires I 4a, I 4b. Annular band 44secured at the upper edge of body member 40 constitutes a second,independent heating coil, the electrical current being conducted to twodiametrical opposite points thereof by wires 44a, 44b. A hole 4| isprovided in th wall of body member 40 through which wires l4a, l4b, 44a,44b pass into the interior of the body member. It is clear that wiresl4a, 44a lead to one terminal of the current source, while wires 14b,44b lead to the other terminal.

An insulating ring 45 having an outwardly turned flange 4B is secured atthe saidflange to the body member 40 to provide an annular recess 41 andto project the upper portion of the insulating ring above the upper edgeof the insulating ring 45. Head plate Illa has an annular groove IS inits underside to receive the upper portion of insulating ring 45. Thespindlefl, its two collars, mounting I, etc. are similar to Fig. 1 andbear the same reference characters. The tubular plastic article and theelastic element are placed onthe apparatus in the manner described abovewith reference to Figs. 1-5 and the head plate moved downwardly tocompress the two folds of the plastic material, see Fig. 5; a switch inthe electrical circuit (not shown) is closed to energize heating coil l4of the head plate Illa and heating coil 44 of the body member 40, toraise their temperature by conductive heating. The conductive heatingarrangement of Fig. 7

may be applied in similar fashion to the doubleelastlc apparatus of Fig.6.

Bifurcated plastic sheet articles. such as baby pants, requiring threeelastic elements-one at each leg and one at the waist-areaccommodated-on the apparatus shown in Fig.8, forsimultaneous sealing ofthe three elastic elements. Body member 50 is open at its lower edge, inwhich is provided an inwardly-disposed annular recess 5| and an annularlip 52. Underlying lower edge 5l-52 of the body member is a bottom platewhich rests on base 9. The upper end of body member 50 is closed by aplate 53 which may be integral therewith. Two spaced circular openings54, 55 are provided in top plate 53. Enclrcling opening 58 is an annularlip 58 and an inwardly-disposed annular shoulder 58; encircling opening55 is an annular lip 59 and an inwardly-disposed annular shoulder 51.Overlying opening 54 is a circular disk 64 provided with anannulargroove 62 and having an annular surface 68; overlying opening 55is a circular disk 65 provided with an annular groove 63 and having anannular surface 69. Secured within circular opening 54 is an insulatingring 12, the upper portion of which is slidably received in annulargroove 62 of disk 64; secured within circular opening 55 is aninsulating ring 13, the upper portion of which is slidably received inannular groove 63 of disk 65. Disk 64 is mounted by a central post 66 toa supporting plate 60; disk 65 is mounted to the supporting plate 60 bya central post 61.

Supporting plate 60 is mounted at the upper end of a vertical spindle 30which has a collar 35 in underlying relation to plate 60. Spindle 30 isslidably disposed in central bearin openings 9a, 10a in the base 9 andbottom plate 10, respectively; a collar 38 is secured to thespindle inunderlying relation to base 9. A third collar 36 is secured to thespindle and a compression coil spring 48 interposed between it and thebottom plate 10. Body member 50 is mounted on plate 60 by means of anannular flanged ring 59' which is secured at its neutral flange to thebody member and which rests on the plate 60, or rather, on an annularledge 6| thereof. In the previous figures, the insulating rings (such as23 in Fig. 1 and Fig. 6, and 23 in Fig. 6) were described and shown asbeing secured to the body member. The insulating rings 13,12 of Fig. 8are secured in this manner. The insulating rings may be secured to theend plates, either the head plate or the bottom plate; this alternativeconstruction is shown in Fig. 9 where the insulating ring 14 is securedto the bottom plate 10, more particularly, in an annular groove 1|thereof.

The bifurcated article, such as a pair, of baby pants, is placed on theapparatus with the waist portion thereof disposed at the space betweenthe lower end of body member 50 and bottom plate 10 and with one legopening at the space between disk 65 and opening 55 of the body memberand with the other leg opening at the space between disk 64 and theopening 54. A large elastic element is placed at the waist portion andtwo smaller elements at each of the leg openings,

and released to form inwardly-turned folds (of. Fig. 4). The two disks64, 65 are thenforced downwardly. moving supporting plate 60 (to whichthey are connected by posts 55, 61) in that direction together withspindle 30*. This compresses the folded plastic material at the twolegs. Further pressure on the disks causes the lower edge of body member50 to compress the folded plastic material between it and bottom plat10. i. e., at the waist of the garment. The electrical connection inFig. 8 may be either that of Figs. 1 and 6 (di-electric heating) or thatof Fig. 7 (conductive heating). It is shown as in Figs. 1 and 6.

The apparatus of Fig. 9 is also designed for bifurcated garments, suchas baby pants, but differs from that of Fig. 8 in that the apparatus ofFig. 8 is for baby pants having legs or leg openings extending straightand parallel from the body portion. while the machine of Fig. 9 is forbifurcated garments in which the leg openings or legs extend outwardlyat an angle. Body member is open at its lower edge which is opposite anannular bottom ring 15 having an annular groove 16 in which is slidinglyreceived an insulating ring 11; bottom ring 15 rests on base 18. Theupper end of body member 80 is closed at 83 and has two circularopenings 84, 85 disposed at an angle to the central axis of the bodymember. Encircling opening 84 is a flange of a length depending upon thelength of the leg of the garment, and spaced outwardly from the openingto provide an annular ledge 86'. Seated on ledge 86' is an insulatingdisk 88. overlying flange 85 is a circular disk H4 to which is securedinsulating ring or tube H2. A hearing bushing 92 is centrally secured ininsulating disks I 88 and slidably supports a spindle 82 to which issecured a collar 96 near its lower end;- theupper end of spindle 82 issecured to circular disk 5. Interposed between bearing bushing 92 andcollar 96 is a tensile spring 94 secured at its ends to the bushing 92and collar 96, respectively. The other opening 85 of the body member 80has a similar flange 81, annular ledge 81', insulating disk 89, circulardisk H5, insulating tube or ring Ill, bearing bushing 91, spindle 8i,tensile spring 93, and collar 95. The body member 80 is provided withtwo bracket arms 80' of suitable insulating material which presentdistal platforms 80a,80a in underlying and spaced relation to therespective openings 85, 84.

A main spindle Hill is centrally disposed within body member 80 and hasa collar "H. A flexible wire 91 is connected at one end to the lower endof leg spindle 8| and connected at the other end to a distal point ofcollar IN; a similar flexible wire 9 8 is connected between leg spindle82 and the collar Illl. Flexible wires 91, 98 pass through apertures80b, 80b in the bracket platforms 80a.

Secured to body member 80 is a flanged plate 800 of suitable insulatingmaterial provided with a central opening for main spindle 100.Underlying insulated plate 800 is a spindle collar I03. Interposedbetween collar II and insulated plate lie is a compression spring Ill.Spindle III has a third collar llll, interposed between which and abearing III secured to base ll is a second compression spring I". Afourth collar Ill underlies base ll. Base 10 has an opening II for anelectrical wire 42 which is connected to body member ll; the other wire43 is connected to base ll. Heating is by the inductive method (Figs.1-6). The connection 48 to the base ll supplies current to bottom ringI! and via the main spindle I and flexiblewlres 91, ll, to the circulardisks II, II, of the two leg openings ll, 84, respectively. The otherconnection 42 supplies current directly to the lower edge of the bodymember and to its two upper annular flanges ll, 88 at the leg openings.

- After the garment is placed on the apparatus together with the threeelastic elements, main spindle III is forced downwardly, firstovercoming, say, compression spring Hi2. The downward movement' of itscollar lili pulls the two flexible wires TI, '8 to draw spindles ll, 82downwardly to cause the circular disks H5, ill to approach the upperedge of annular leg flanges I1, It. Further downward movement of spindleIll, this time overcoming the other compression spring III, causes alowering of body member III to approach the floor ring 15.

The elastic element E, see Figs. 3, 4 and 5,

may be continuous, i. e., the encircling element B may be elastic at allpoints of its circumference; in this case, the annular electrodes(annular lip 22 and including recess 2|, of the body member 2| and theannular surface. II of the head plate) would likewise be continuous. Incertain cases the elastic element need not be sealed all around itsencircling circumference, or may be discontinuous; in this case theelectrodes would be made discontinuous in conformity with therequirements of the elastic element and its sealing in the plasticarticle.

I claim:

1. Apparatus for affixing an elastic element to a flexible plastic sheetarticle at a predetermined point thereof, comprising a tubular bodymember having at one edge thereof an inwardly-disposed annular recessand an outer annular lip, a ring secured to the inside surface of thetubular body member a portion thereof extending beyond said edge, an endplate having an annular groove for slidably receiving the said extendedportion of the ring and an outer annular surface confronting the saidannular lip of the body member, said end plate and body member beingnormally separated to provide a space therebetween, said article beingpositionable on the apparatus with its said predetermined point at thesaid space and with said elastic element in tensioned conditionencircling the article at said space whereby contraction of thetensioned elastic element crimps the article inwardly to form a fold ofthe plastic sheet in the said space with the contracted element in thebight thereof and encircling the said ring, said end plate being mountedfor axial movement towards the body member to reduce the said spacetherebetween and to compress the plies of said fold between its saidannular surface and the said annular lip of the body member, the saidelastic element and bight of the fold being received in the said annularrecess of the body member.

2. Apparatus for afilxing an elastic element to a flexible plastic sheetarticle at a predetermined point thereof, comprising a tubular bodymember, an end member disposed opposite one edge 8 thereof, one of thesaid members having an inwardly-disposed annular recess and an outerannular lip, and the other member having an annular surface opposite thesaid annular recess and lip of the other member, a ring disposedinwardly of and adjacent to said annular recess and annular surface ofthe two members, said members being normally separated to provide aspace therebetween, said article beingpositionable on the apparatus withits said predetermined point at the said space and with said elasticelement in tensioned condition encircling the article at said spacewhereby contraction of the tensioned elastic element crimps the articleinwardly to form a fold of the plastic sheet in the said space with thecontracted elastic element in the bight thereof and encircling the saidring, said members being mounted for relative axial movement to reducesaid space and to compress the piles of said fold between said annularlip and annular surface, the said elastic element and bight of the foldbeing received in the said annular recess.

- 3. Apparatus for amxing an elastic element to a flexible plastic sheetarticle at a predetermined point thereof; comprising a tubular bodymember, an end member disposed opposite one edge thereof, one of thesaid members having an inwardly-disposed annular recess and an outerannular lip, and the other member having an annular surface opposite thesaid annular recess and lip of the other member, a ring disposedinwardly of and adjacent to said annular recess and annular surface ofthe two members, said members being normally separated to provide aspace therebetween, said article being positionable on the apparatuswith its said predetermined point at the said space and with saidelastic element in tensioned condition encircling the article at saidspace whereby contraction of the tensioned elastic element crimps thearticle inwardly to form a fold of the plastic sheet in the said spacewith the contracted elastic element in the bight thereof and encirclingthe said ring, said ,members being mounted for relative axial movementto reduce said space and to compress the piles of said fold between saidannular lip and annular surface, the said elastic element and bight ofthe fold being received in the said annular recess, and means forheating the said annular lip and annular surface to cause adhesion ofthe said piles of saidfold of the plastic article.

4. Apparatus for affixing an elastic element to aflexible plastic sheetarticle at a predetermined point thereof, comprising a tubular bodymember, an end member disposed opposite one edge thereof, one of thesaid members having an inwardly-disposed annular recess and an outerannular lip, and the other member having an annular surface opposite thesaid annular recess and lip of the other member, a ring disposedinwardly of and adi acent to said annular recess and annular surface ofthe two members, said members being normally separated to provide aspace therebetween, said article being positionable on the apparatuswith its said predetermined point at the said space and with saidelastic element in tensioned condition encircling the article at saidspace whereby contraction of the tensioned elastic element crimps thearticle inwardly to form a fold of the plastic sheet in the said spacewith the contracted elastic element in the bight thereof and encirclingthe said ring, said members being mounted for relative axial movement toreduce said space and to compress the plies of said fold between saidannular lip and annular surface, the said elastic element and bight ofthe fold being received in the said annular recess, and a high-frequencyelectrical circuit one terminal of which is connected to one of saidpair of members and the other terminal is connected to the other member,so that when an electrical potential is impressed across the said spaceadhesion of the said plies of said fold of the plastic article occurs.

5. Apparatus for aifixing an elastic element to a flexible plastic sheetarticle at a predetermined point thereof, comprising a tubular bodymember having an annular band secured at one edge, an end plate memberhaving an annular band secured to the underside thereof and aligned withthe said band of the body member, said members being normally separatedto provide a space be tween their respective bands, a ring secured toone of said members and disposed inwardly of its band to provide anannular recess, said articlebeing positionable on the apparatus with itssaid predetermined point at the said space and with said elastic elementin tensioned condition encircling the article at said space wherebycontraction of the tensioned elastic element crimps the article inwardlyto form a fold of the plastic sheet in the said space with thecontracted elastic element in the bight thereof and encircling the saidring, members being mounted for relative axial movement to reduce thesaid space therebetween and to compress the plies of said fold betweentheir bands, the said elastic element and bight of the fold beingreceived in the said annular recess.

6. Apparatus for aflixing an elastic element to a plastic sheet articleat a predetermined point thereof, comprising a tubular body member, anend member disposed opposite one edge thereof, said members havingopposed annular surfaces and being normally separated to provide a spacetherebetween, a ring member disposed inwardly of the said annularsurfaces, the members presenting an annular recess at the outer surfaceof the ring member, said article being positionable on the apparatuswith its said predetermined point at the said space and with saidelastic element in tensioned condition encircling the article at saidspace whereby contraction of the tensioned elastic element crimps thearticle inwardly to form a fold of the plastic sheet in the said spacewith the contracted elastic element in the bight thereof and encirclingthe said ring member, said members being mounted for relative axialmovement to reduce said space and to compress the said fold between saidannular surfaces, the said elastic element and bight of the fold beingreceived in the said annular recess.

7. Apparatus for amxing an elastic element to a plastic sheet article ata predetermined point thereof, comprising a tubular body member, an endmember disposed opposite one edge thereof, said members having opposedannular surfaces and being normally separated to provide a spacetherebetween, a ring member disposed inwardly of the said annularsurfaces, the members presenting an annular recess at the outer surfaceof the ring member, said article being positionable on the apparatuswith its said predetermined point at the said space and with saidelastic element in tensioned condition encircling the article at saidspace whereby contraction of the tensioned elastic element crimps thearticle inwardly to form a fold of the plastic sheet in the said spacewith the contracted elastic element in the bight thereof and encirclingthe said ring member, said members being mounted for relative axialmovement to reduce said space and to compress the said fold between saidannular surfaces, the said elastic element and bight of the fold beingreceived in the said annular recess and means for heating the saidannular surfaces to cause adhesion of the said fold of the plasticarticle.

8. Apparatus for afllxing elastic elements to a flexible plastic sheetarticle at a plurality of predetermined thereof, comprising a tubularbody member, an end member disposed opposite each edge thereof, saidmembers having opposed annular surfaces at each said edge and normallyseparated to provide a space thereat, a ring member at each said edgedisposed inwardly of the said annular surfaces, the members presentingan annular recess at each said edge, said article being positionable onthe apparatus with one of its said predetermined points at each of saidspaces and with an elastic element in tensioned condition encircling thearticle at said spaces whereby contraction of the tensioned elasticelements crimps the article inwardly to form'a fold of the plastic sheetin each of said spaces with the contracted elastic elements in the bightthereof and encircling the respective ring members, said members beingaxially movable to re duce the said spaces and to compress the saidfolds between the annular surfaces, the said elastic elements and bightsof the folds being received in the said annular recesses.

9. Apparatus for afllxing elastic elements to a flexible plastic sheetarticle at a plurality of predetermined points thereof, comprising atubular body member, an end member disposed opposite each edge thereof,said members having opposed annular surfaces at each said edge andnormally separated to provide a space thereat, a ring member at eachsaid edge disposed inwardly of the said annular surfaces, the memberspresenting an annular recess at each said edge, said article beingpositionable on the apparatus with one of its said predetermined pointsat each of said spaces and with an elastic element in tensionedcondition encircling the article at said spaces whereby contraction ofthe tensioned elastic elements crimps the article inwardly to form afold of the plastic sheet in each of said spaces with the contractedelastic elements in the bight thereof and encircling the respective ringmembers, said members being axially movable to reduce the said spacesand to compress the said folds between the annular surfaces, the saidelastic elements and bights of the folds being received in the saidannular recesses, and means for heating the said annular surfaces tocause adhesion of the said folds of the plastic article.

10. The combination according to claim 8 wherein one of the end membersis a secured base member and the other end member is mounted for axialmovement relative to the body member and the body member is mounted foraxial movement relative to the base member.

11. An apparatus to form a hem around a continuous portion of a sheet ofmaterial, with an elastic band confined within the hem in the bightthereof said apparatus comprising two relatively, co-axially movable,normally spaced apart, hollow dies, a gage block within said die andhaving a peripheral conformation substantially parallel to the innerperimeter of at least one of the dies, said gage block being spacedapart from said inner perimeter whereby when the dies are 11 broughttogether for uniting the plies of the hem, the bight of the hem will befree of the die.

12. An apparatus to form a hem around a continuous portion of sheetmaterial with a tunnel adjacent the bight of the hem enclosing anelastic band said apparatus comprising relatively movable coacting dies,one of the dies being provided with a groove to accommodate the bight ofthe hem, when the elastic band is placed over the sheet materialoverlying said groove whereby to tuck the sheet material into saidgroove, means to fold over the material to form all portions of the hemsubstantially simultaneously, and means simultaneously to unite theentire hem around said die.

13. In an apparatus for forming a hem around a continuous portion of asheet of material with an elastic element confined within the hemadjacent the bight thereof; a die assembly having two relativelyco-axially movable normally spaced apart portions which have coactingfaces remote from the common axis of said portions, a gage radiallyinward of the coacting faces constructed and arranged to extend past thespace between said faces and to be sufliciently spaced apart from theinterface region or zone formed by the coacting faces, to accommodatethe elastic element and the bight of the hem when said faces are broughttoward each other.

14. The die assembly as claimed in claim 13 further characterized bysaid portions being electrically insulated from each other to permitdielectric heat to be applied'and thereby uniting the piles of the hemformed between the dies.

15. An apparatus as called for in claim 13,

further characterized by the provision of power means to cause a meetingof adjacent surfaces to '12 apply pressure to the confined hem to unitethe plies thereof.

16. An apparatus as called for in claim 13 further characterized by theprovision of heating means in die assembly so that movement of said dieportions toward each other causes meeting of adjacent surfaces therebyto apply heat to the confined hem to unite the plies thereof.

17. An apparatus to form a hem around a continuous portion of sheetmaterial with a tunnel adJacent the bight of the hem enclosing anelastic band, said apparatus comprising relatively movable coactingdies, one of the dies being provided with a groove to accommodate thebight of the hem when the elastic band is placed over the sheet materialoverlying said grooves whereby to tuck the sheet material into saidgroove, and means simultaneously to ,unite the entire hem around saiddie, said portions being electrically insulated from each other topermit dielectric heat to be applied and thereby uniting the plies ofthe hem formed between the dies.

SIDNEY H. MAGID.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1 1,755,926 Leguillon et al Apr.22, 1930 2,231,457 Stephen Feb. 11, 1941 2,259,508 Abramson Oct. 21,1941 2,304,852 Sharples Dec. 15, 1942 2,412,693 Pierson Dec. 17, 1946

